Until now, such parts which form the outer shell of a satellite-support structure of a space launcher in the above-mentioned example, are made and then stored separately prior to being assembled together by means of breakable joint systems. Thus, because of the large sizes of such parts (which may, in some cases, reach several meters in diameter) or because of their complex shapes, systems are designed for being fitted thereto.
To assemble together two parts that are designed subsequently to be separated from each other, conventional breakable joint systems comprise two frames each having a fork or clevis shape at one end for receiving the corresponding edge of one of the parts, which edge is held therein by glue and/or by bolts passing radially through the final assembly. The system further includes interconnection plates enabling the facing opposite ends of the frames to be assembled together by means of bolts, which plates are disposed to overlie each other on opposite sides of said ends of the frames. The explosive fuse cord is inserted in conventional manner in an expansible tube in order to avoid subsequent pollution of space, and it is housed in a fuse-receiving housing delimited by the overlying interconnection plates and by the corresponding ends of the frames which penetrate between said plates. Zones of weakness are provided on said plates so that when the fuse is caused to explode, the expansible tube breaks the plates in said zones, thereby separating the two parts.
Although it operates satisfactorily, this type of breakable joint system nevertheless suffers from drawbacks, in particular because its very structure requires said explosive fuse and said plates to be assembled to said frames as individual parts which means that installing the plates and the explosive fuse on said frames is lengthly and difficult. In addition, by using said frames, such a conventional joint system presents significant mass and bulk. Since the safety requirements in the intended fields of application are extremely severe, it is not easy to reduce the mass of the system. Further, the design of such a prior art system gives rise to an embodiment which is clearly symmetrical such that the explosive fuse is disposed in the transverse midplane of the plates at equal distances from the connections between the plates and the frames, and this does not optimize the breaking force delivered by the fuse.
An object of the present invention is to mitigate these drawbacks and to provide a breakable joint system enabling parts, in particular the top structures of a space launcher, to be separated by means of an explosive charge, the design of the system being simple and making it easy to assemble the system on said parts while reducing the mass of the system and optimizing the breaking force produced by the explosive charge.